As electrically conductive pastes or electrically conductive compositions, dispersions have been obtained by adding an organic binder and optionally a solvent and additives to powder of, for example, any of the following metals: noble metals, such as gold, platinum, palladium, silver, and silver-palladium [for instance, Jap. Pat. Appln. Kokai (Laid-Open) Nos. SHO 56 (1981)-70064, SHO 51 (1976)-124655, SHO 59 (1984)-45355, and HEI 1 (1989)-98674], nickel [for instance, Jap. Pat. Appln. Kokai (Laid-Open) SHO 58 (1983)-53966], silver-plated copper [for instance, Jap. Pat. Appln. Kokai (Laid-Open) Nos. SHO 56 (1981)-8892 and HEI 1 (1989)-231208], and copper [for instance, Jap. Pat. Appln. Kokai (Laid-Open) Nos. SHO 56 (1981)-163166, SHO 62 (1987)-74967, SHO 63 (1988)-89577, SHO 57 (1982)-55974 and HEI 2 (1990)-16172].
The conventional electrically conductive pastes have the following defects. Copper is not expensive but oxidation tends to decrease its electroconductivity. Addition of an antioxidant to paste obtained with copper powder has also been tried. In such case, in an early stage, copper oxide is removed from particle surfaces and electroconductivity can be attained. But, after the paste is made into a coating film, the contact resistance is gradually increased at high temperatures or high humidities, resulting in low electroconductivity. Electrically conductive pastes obtained by the use of silver powder are well known but involve an electromigration problem. Electrically conductive pastes obtained by the use of powder produced by plating copper powder with silver are also well known, but it is difficult to plate fine powder uniformly with silver and these pastes encounter a problem when a plated silver film comes off and an electromigration problem. Furthermore, a local battery cell tends to form between silver and copper, so that copper is easily oxidized. Processes for mechanically alloying silver with, copper forcedly have been disclosed [for example, Jap. Pat. Appln. Kokai (Laid-Open) Nos. SHO 56 (1981)-155259 and SHO 57 (1982 )-98572], but are disadvantageous in that because of the mechanical alloying, the processes are not sufficiently effective in preventing the electromigration of silver.